Pulmonary pharmacology & therapeutics
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Pulm Pharmacol Ther · Jan 2004
Comparative StudyComparative effects of dopamine and dobutamine on hypercapnic depression of diaphragmatic contractility in dogs.
The present study was undertaken to evaluate the effects of dopamine and dobutamine on diaphragmatic contractility in dogs with induced hypercapnia. Animals were divided into three groups of ten each. In each group, hypercapnia (80-90 mmHg) was produced by adding 10% CO2 to the inspired gas. ⋯ The increase in Pdi was more than in Group III than in Group II (P<0.05). In Group I, Pdi to each stimulus did not change from hypercapnia-induced values. In conclusion, compared with dopamine, dobutamine is effective in improving hypercapnic depression of diaphragmatic contractility in dogs.
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Pulm Pharmacol Ther · Jan 2004
Randomized Controlled Trial Comparative Study Clinical TrialBudesonide/formoterol in a single inhaler rapidly relieves methacholine-induced moderate-to-severe bronchoconstriction.
Inhalers containing corticosteroids and long-acting beta2-agonists are becoming increasingly important in asthma management. A rapid effect is important to patients, particularly during exacerbations. We compared the onset of bronchodilation and patient-perceived relief from dyspnoea following single-inhaler budesonide/formoterol or salmeterol/fluticasone in a model of acute bronchoconstriction. ⋯ Median recovery times to 85% of baseline FEV1 were shorter for budesonide/formoterol (1 or 2 inhalations: 3.3 and 2.8 min, respectively) than salmeterol/fluticasone (8.9 min; P < 0.001) and placebo (> 30 min). One min after budesonide/formoterol, dyspnoea was significantly reduced (Borg score -0.86 units, both doses) compared with salmeterol/fluticasone (-0.55 units; P < 0.05) and placebo (-0.23 units; P < 0.001). Budesonide/formoterol provides immediate bronchodilation, faster than salmeterol/fluticasone, which patients can feel during acute methacholine-induced bronchoconstriction.
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Stimulation of laryngeal receptors is the natural starting point of defensive airway reflexes including the cough reflex, expiration reflex, spasmodic panting, and apnoea with laryngospasm. Although several different types of laryngeal receptors have been reported, the laryngeal irritant receptors are considered to play the most essential role in elicitation of defensive airway reflexes. Based on the knowledge that the laryngeal irritant receptors are stimulated by water solutions lacking chloride anions, we have developed an experimental method to elicit defensive airway reflexes with a direct instillation of distilled water onto the laryngeal mucosa in humans. ⋯ The reflex responses to water stimulation observed in these patients were characterized by apnoea with laryngospasm while the cough reflex was never elicited. Endoscopic images of the larynx in these patients were also characterized by laryngeal oedema. Considering the pathological changes occurring in the central nervous system and the laryngeal mucosa, it is possible that the defensive airway reflexes may be modified by central and/or peripheral mechanisms in patients with MSA.
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Chronic and uncontrollable cough is one of the most common and debilitating symptoms found in patients with chronic airway diseases. The physical trauma and stresses of chronic cough on the airway mucosa and respiratory muscles can further worsen the deteriorating process of the airway diseases. ⋯ A number of new and important questions concerning the physiological and pharmacological mechanisms underlying chronic cough have emerged in these presentations. Further studies are required to answer these questions, which should bring a better understanding of the pathogenic mechanisms of chronic cough and lead to the development of new therapeutic strategies.
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Pulm Pharmacol Ther · Jan 2004
Inhaled milrinone for the improvement of contractility of fatigued diaphragm in dogs: a dose-ranging study.
The present study was undertaken to evaluate the efficacy of inhaled milrinone on contractility of fatigued diaphragm in dogs. Animals were divided into four groups of seven each. In each group, diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. ⋯ The increase in Pdi was more in Group IV than in Group III (P<0.05). Compared with Group I, Pdi to each stimulus did not change in Group II. In conclusion, inhaled milrinone, in doses more than 0.2 mg/ml, is effective for improving contractility of fatigued diaphragm in dogs.